Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in JAVA):

Solution:
import java.util.*;
import java.io.*;
import java.math.BigInteger;
 
/**
 *
 * @author usquare
 */
//816C
public class ProblemB {
    
    static long mod = (int) (1e9+7);
    static InputReader in;
    static PrintWriter out;
    
    static void solve(){
        in = new InputReader(System.in);
        out = new PrintWriter(System.out);

        int n = in.ni();
        int m = in.ni();
        int[][] arr = new int[n][m];
        
        for(int i=0;i<n;i++)
            arr[i] = in.nextIntArray(m);
        
        for(int i=1;i<m;i++){
            for(int j=0;j<n;j++){
                if(arr[j][i]-arr[j][i-1] != arr[0][i]-arr[0][i-1]){
                    System.out.println("-1");
                    System.exit(0);
                }
            }
        }
        ArrayList<String> list = new ArrayList<>();
        if(n<m){
            for(int i=0;i<n;){
                boolean f=true;
                for(int j=0;j<m;j++) if(arr[i][j]==0){
                    f=false;
                    break;
                }
                if(!f) i++;
                else{
                    list.add("row "+(i+1));
                    for(int j=0;j<m;j++) arr[i][j]--;
                }
            }
            for(int i=0;i<m;){
                boolean f=true;
                for(int j=0;j<n;j++) if(arr[j][i]==0){
                    f=false;
                    break;
                }
                if(!f) i++;
                else{
                    list.add("col "+(i+1));
                    for(int j=0;j<n;j++) arr[j][i]--;
                }
            }
        }
        else{
            for(int i=0;i<m;){
                boolean f=true;
                for(int j=0;j<n;j++) if(arr[j][i]==0){
                    f=false;
                    break;
                }
                if(!f) i++;
                else{
                    list.add("col "+(i+1));
                    for(int j=0;j<n;j++) arr[j][i]--;
                }
            }
            for(int i=0;i<n;){
                boolean f=true;
                for(int j=0;j<m;j++) if(arr[i][j]==0){
                    f=false;
                    break;
                }
                if(!f) i++;
                else{
                    list.add("row "+(i+1));
                    for(int j=0;j<m;j++) arr[i][j]--;
                }
            }
        }
        out.println(list.size());
        for(String s:list) out.println(s);
        
        out.close();
    }
    
    public static void main(String[] args) {
 
        new Thread(null,new Runnable() {
            @Override
            public void run() {
                try{
                    solve();
                }
                catch(Exception e){
                    e.printStackTrace();
                }
            }
        },"1",1<<26).start();
    }
    
    static class Pair implements Comparable<Pair>{
 
        int x,y;
        int i;
        
	Pair (int x,int y,int i){
		this.x=x;
		this.y=y;
		this.i=i;
	}
 
	Pair (int x,int i){
		this.x=x;
		this.i=i;
	}
        
	public int compareTo(Pair o) {
            return Long.compare(this.x,o.x);
		//return 0;
	}
 
            public boolean equals(Object o) {
            if (o instanceof Pair) {
                Pair p = (Pair)o;
                return p.x == x && p.y == y && p.i==i;
            }
            return false;
        }
 
        @Override
        public String toString() {
            return x+" "+y+" "+i;
        }
        
    } 
    
    static class Merge {
        
        public static void sort(long inputArr[]) {
            int length = inputArr.length;
            doMergeSort(inputArr,0, length - 1);
        }
        
        private static void doMergeSort(long[] arr,int lowerIndex, int higherIndex) {        
            if (lowerIndex < higherIndex) {
                int middle = lowerIndex + (higherIndex - lowerIndex) / 2;
                doMergeSort(arr,lowerIndex, middle);
                doMergeSort(arr,middle + 1, higherIndex);
                mergeParts(arr,lowerIndex, middle, higherIndex);
            }
        }
        
        private static void mergeParts(long[]array,int lowerIndex, int middle, int higherIndex) {
            long[] temp=new long[higherIndex-lowerIndex+1];
            for (int i = lowerIndex; i <= higherIndex; i++) {
                temp[i-lowerIndex] = array[i];
            }
            int i = lowerIndex;
            int j = middle + 1;
            int k = lowerIndex;
            while (i <= middle && j <= higherIndex) {
                if (temp[i-lowerIndex] < temp[j-lowerIndex]) {
                    array[k] = temp[i-lowerIndex];
                    i++;
                } else {
                    array[k] = temp[j-lowerIndex];
                    j++;
                }
                k++;
            }
            while (i <= middle) {
                array[k] = temp[i-lowerIndex];
                k++;
                i++;
            }
            while(j<=higherIndex){
                array[k]=temp[j-lowerIndex];
                k++;
                j++;
            }
        }
 
    }
    
    static long add(long a,long b){
        long x=(a+b);
        while(x>=mod) x-=mod;
        return x;
    }
 
    static long sub(long a,long b){
        long x=(a-b);
        while(x<0) x+=mod;
        return x;
    }
    
    static long mul(long a,long b){
        a%=mod;
        b%=mod;
        long x=(a*b);
        return x%mod;
    }
 
    
    static boolean isPal(String s){
        for(int i=0, j=s.length()-1;i<=j;i++,j--){
                if(s.charAt(i)!=s.charAt(j)) return false;
        }
        return true;
    }
    static String rev(String s){
		StringBuilder sb=new StringBuilder(s);
		sb.reverse();
		return sb.toString();
    }
    
    static long gcd(long x,long y){
	if(y==0)
		return x;
	else
		return gcd(y,x%y);
    }
    
    static int gcd(int x,int y){
	if(y==0)
		return x;
	else 
		return gcd(y,x%y);
    }
    
    static long gcdExtended(long a,long b,long[] x){
        
        if(a==0){
            x[0]=0;
            x[1]=1;
            return b;
        }
        long[] y=new long[2];
        long gcd=gcdExtended(b%a, a, y);
        
        x[0]=y[1]-(b/a)*y[0];
        x[1]=y[0];
        
        return gcd;
    }
    
 
    static long mulmod(long  a,long b,long m) {
        if (m <= 1000000009) return a * b % m;
 
        long res = 0;
        while (a > 0) {
            if ((a&1)!=0) {
                res += b;
                if (res >= m) res -= m;
            }
            a >>= 1;
            b <<= 1;
            if (b >= m) b -= m;
        }
        return res;
    }
    
    static int abs(int a,int b){
	return (int)Math.abs(a-b);
    }
 
    public static long abs(long a,long b){
	return (long)Math.abs(a-b);
    }
    
    static int max(int a,int b){
	if(a>b)
		return a;
	else
		return b;
    }
 
    static int min(int a,int b){
	if(a>b)
		return b;
	else 
		return a;
    }
    
    static long max(long a,long b){
	if(a>b)
		return a;
	else
		return b;
    }
 
    static long min(long a,long b){
	if(a>b)
		return b;
	else 
		return a;
    }
 
    static long pow(long n,long p,long m){
	 long  result = 1;
	  if(p==0)
	    return 1;
          
	while(p!=0)
	{
	    if(p%2==1)
	        result *= n;
	    if(result>=m)
	    result%=m;
	    p >>=1;
	    n*=n;
	    if(n>=m)
	    n%=m;
	}
	return result;
    }
    
    static long pow(long n,long p){
	long  result = 1;
	  if(p==0)
	    return 1;
          
	while(p!=0)
	{
	    if(p%2==1)
	        result *= n;	    
	    p >>=1;
	    n*=n;	    
	}
	return result;
    }
    
    static void debug(Object... o) {
            System.out.println(Arrays.deepToString(o));
    }
     
    static class InputReader {
    
        private final InputStream stream;
        private final byte[] buf = new byte[8192];
        private int curChar, snumChars;
        private SpaceCharFilter filter;
 
        public InputReader(InputStream stream) {
                this.stream = stream;
        }
 
        public int snext() {
                if (snumChars == -1)
                        throw new InputMismatchException();
                if (curChar >= snumChars) {
                        curChar = 0;
                        try {
                                snumChars = stream.read(buf);
                        } catch (IOException e) {
                                throw new InputMismatchException();
                        }
                        if (snumChars <= 0)
                                return -1;
                }
                return buf[curChar++];
        }
 
        public int ni() {
                int c = snext();
                while (isSpaceChar(c)) {
                        c = snext();
                }
                int sgn = 1;
                if (c == '-') {
                        sgn = -1;
                        c = snext();
                }
                int res = 0;
                do {
                        if (c < '0' || c > '9')
                                throw new InputMismatchException();
                        res *= 10;
                        res += c - '0';
                        c = snext();
                } while (!isSpaceChar(c));
                return res * sgn;
        }
 
        public long nl() {
                int c = snext();
                while (isSpaceChar(c)) {
                        c = snext();
                }
                int sgn = 1;
                if (c == '-') {
                        sgn = -1;
                        c = snext();
                }
                long res = 0;
                do {
                        if (c < '0' || c > '9')
                                throw new InputMismatchException();
                        res *= 10;
                        res += c - '0';
                        c = snext();
                } while (!isSpaceChar(c));
                return res * sgn;
        }
 
        public int[] nextIntArray(int n) {
                int a[] = new int[n];
                for (int i = 0; i < n; i++) {
                        a[i] = ni();
                }
                return a;
        }
 
        public long[] nextLongArray(int n) {
                long a[] = new long[n];
                for (int i = 0; i < n; i++) {
                        a[i] = nl();
                }
                return a;
        }
 
        public String readString() {
                int c = snext();
                while (isSpaceChar(c)) {
                        c = snext();
                }
                StringBuilder res = new StringBuilder();
                do {
                        res.appendCodePoint(c);
                        c = snext();
                } while (!isSpaceChar(c));
                return res.toString();
        }
 
        public String nextLine() {
                int c = snext();
                while (isSpaceChar(c))
                        c = snext();
                StringBuilder res = new StringBuilder();
                do {
                        res.appendCodePoint(c);
                        c = snext();
                } while (!isEndOfLine(c));
                return res.toString();
        }
 
        public boolean isSpaceChar(int c) {
                if (filter != null)
                        return filter.isSpaceChar(c);
                return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
        }
 
        private boolean isEndOfLine(int c) {
                return c == '\n' || c == '\r' || c == -1;
        }
 
        public interface SpaceCharFilter {
                public boolean isSpaceChar(int ch);
        }
        
    }
}